Question 1051433
A five digit-number: 
A B C D E
:
the first two digits are the same;
A A C D E 
:
the sum of the two digits equals the two-digit number formed by reading the third and fourth digits together;
2A = 10C + D
From this we know that C = 1, and D is an even number
:
 the last digit is the sum of the third and fourth digits,
E = C + D
E = D + 1
:
 and is also one half of the first digit.
{{{1/2}}}A = E
A = 2E
we know E = D+1, and C = 1 therefore
A = 2(D+1)
Now our number
2(D+1), 2(D+1), 1, D, (D+1)
We know the D is even, A < 10, so D=2
6, 6 , 1, 2, 3
:
 what is the number? 66123, note the sum of the 1st two digits = 12